XML/Projectile particle

This article documents Glest, GAE, and MegaGlest This is noted in the colored backgrounds, which denote lines as being engine specific. See the key below.[Editing help]

The Projection Particle XML defines the visual effects as well as part of the mechanics used to for attacks between units.

XML

GAE Only

MegaGlest Only

GAE and MegaGlest Only

<?xml version="1.0" standalone="yes"?>
<projectile-particle-system>
	<texture value="true" luminance="true" path="texture_name.bmp"/>
	<model value="true" path="model_name.g3d"/>
	<primitive value="quad"/>
	<mode value="normal"/>
	<offset x="0" y="0.2" z="1"/>
	<color red="1.0" green="0.5" blue="0.0" alpha="0.5" />
	<color-no-energy red="0.0" green="0.0" blue="0.0" alpha="0.2" />
	<size value="6" />
	<size-no-energy value="4" />
	<speed value="0" />
	<gravity value="0"/>
	<emission-rate value="1" />
	<energy-max value="20" />
	<energy-var value="0" />
	<!-- Start MG Only -->
    <child-particles value="true">
    	<particle-file path="particle.xml">
    		<offset x="0.5" y="0.5" z="0"/>
    		<radius value="0.1"/>
    		<size value="0.1"/>
    		<gravity value="0"/>
    		<direction x="0" y="0" z="-2"/>
    	</particle-file>
    </child-particles>
	<!-- End MG Only -->

	<trajectory type="linear">
		<speed value="14"/>
		<!-- Start GAE Only -->
		<start value="self"/>
		<start-offset x="0" y="0" z="0"/>
		<start-offset-var x="0" y="0" z="0"/>
		<end value="target"/> 
		<end-offset x="0" y="0" z="0"/>
		<end-offset-var x="0" y="0" z="0"/>
		<tracking value="false"/>
		<!-- End GAE Only -->
	</trajectory>
	<trajectory type="parabolic">
		<speed value="16"/>
		<scale value="2.5"/>
		<!-- Start GAE Only -->
		<start value="self"/>
		<start-offset x="0" y="0" z="0"/>
		<start-offset-var x="0" y="0" z="0"/>
		<end value="target"/> 
		<end-offset x="0" y="0" z="0"/>
		<end-offset-var x="0" y="0" z="0"/>
		<tracking value="false"/>
		<!-- End GAE Only -->
	</trajectory>
	<trajectory type="spiral">
		<speed value="4.0"/>
		<scale value="1"/>
		<frequency value="0.5"/>
		<!-- Start GAE Only -->
		<start value="self"/>
		<start-offset x="0" y="0" z="0"/>
		<start-offset-var x="0" y="0" z="0"/>
		<end value="target"/> 
		<end-offset x="0" y="0" z="0"/>
		<end-offset-var x="0" y="0" z="0"/>
		<tracking value="false"/>
		<!-- End GAE Only -->
	</trajectory>
	<!-- Start GAE Only -->
	<trajectory type="random">
		<speed value="100.0"/>
		<scale value="0.3125"/>
		<frequency value="8"/>
		<start value="target"/>
		<start-offset x="0" y="30" z="0"/>
		<start-offset-var x="4" y="0" z="4"/>
		<end value="target"/> 
		<end-offset x="0" y="0" z="0"/>
		<end-offset-var x="0" y="0" z="0"/>
		<tracking value="true"/>
	</trajectory>
	<blend-mode src="mode" dest="mode"/>
	<blend-equation mode="mode"/>
	<!-- End GAE Only -->
</projectile-particle-system>

Documentation

Comparison of luminance on and off, using the texture at the top-right corner.

texture

Particles can use textures to shape how the particles should look. If luminance is turned on, the image file used as a texture will simply work to define the intensity of the colors. If luminance is turned off, the colors in the image file will be used in the particle. The path is the path to the image.

model

If true, the path to the model which will be used as the attack projectile. Animated models will only show the last frame.

primitive

Particles have two methods of creation: either quad (renders a set of four particles in a dot style) or line (creates solid lines). Quad is the most commonly used, as it creates the fuzzy style of particles that would be used for flames, explosions, smoke, etc, while lines are generally only used for projectiles such as an arrow. Note that you cannot have more than one particle effect linked to a projectile or splash (though you can for unit particle effects) yet, so it is not possible to mix particles (such as a line and flaming particles for a flaming arrow).

mode

Particles have two modes of rendering, either normal which uses colors, or as black which allows the usage of black particles. If not specified, it defaults to normal.

color and color-no-energy

If luminance is off, the colors of the texture will be used to color the particles. If luminance is on, the colors defined in the XML are used, though the intensity and shape will be defined by the texture. There are two colors values, the first which is the color at the start of the particle's life, and the second which defines the color when the particle is dead. Thus, the particles can transition in color. Colors are rendered by mixing red, green, and blue, as well as you can set the alpha channel. Each parameter is from 0 - 1, where 1 means there is 100% of that color. With the alpha, 1 would mean the color is almost completely transparent while 0 would be completely opaque.

size and size-no-energy

While the shape - and thus some degree of the size - is defined by the texture, the size is also affected by the size parameter passed into the XML, which will define the size in game units. Like the color, there are two size values that define the starting and ending sizes. As a result, the particles can seem to shrink or grow over their life.

gravity

Glest has a simple gravity system which can also cause particles to sink downwards - or float upwards - over their life. The value is the degree of sink - or in the case of a negative number, the degree of rise.

trajectory

There are four types of trajectories, linear (straight line), parabolic (arc), spiral (spinning spiral), and random (projectile arcs from multiple points in random directions, eg: lightning).

Table of trajectory values by type

Type of trajectory	Element	Description
linear	speed	How fast the particle moves. Note that speed values over 25 without a splash will nearly always miss due to a bug.
parabolic	speed	How fast the particle moves. Note that speed values over 25 without a splash will nearly always miss due to a bug.
	scale	The angle of the parabola. Higher numbers means it will arc more. For example, with 90, it would shoot almost straight up.
spiral	speed	How fast the particle moves. Note that speed values over 25 without a splash will nearly always miss due to a bug.
	scale	The angle of the parabola. Higher numbers means it will arc more. For example, with 90, it would shoot almost straight up.
	frequency	How many times the spiral will spiral around.
random	speed	How fast the particle moves.
	scale	The degree of angle (in decimal form) that must be changed at each "joint".
	frequency	How many "joints" the projectile will have. At each "joint", it will change direction in a random way.
Any of the above (GAE Only, all optional)	start	Can be either self or target. Where the projectile starts. Default is self.
	start-offset	Specify an offset from where the attack starts. Measurements are cells in the game's 3D grid.
	start-offset-var	Allows you to randomize the offset of the start location of the attack.
	end	Can be either self or target. Where the projectile ends. Default is target.
	end-offset	Specify an offset from where the attack ends. Measurements are cells in the game's 3D grid.
	end-offset-var	Allows you to randomize the offset of the end location of the attack.
	tracking	If true, the particle will change course to follow its target. Default is false.

blend-mode

GAE supports choosing the OpenGL blend mode of the particles, allowing you to set the source and destination blending from these possible options:

• zero
• one
• src_color
• one_minus_src_color
• dst_color
• one_minus_dst_color
• src_alpha
• one_minus_src_alpha
• dst_alpha
• one_minus_dst_alpha
• constant_color
• one_minus_constant_color
• constant_alpha
• one_minus_constant_alpha
• src_alpha_saturate

The destination cannot be set to 'src_alpha_saturate'. If none is selected, the default is equal to the source being 'src_alpha' and the destination being 'one'.

blend-equation (GAE only)

GAE supports choosing the blending equation from these possible options:

• func_add
• func_subtract
• func_reverse_subtract
• min
• max

The default is 'func_add'.

See also

• XMLs
• Particles
• MegaGlest
• GAE